The current IOS5 Beta programme includes updates to the iPhone4 baseband. This new baseband version, 04.11.08, blocks the Gavey Ultra SIM as well as adding other enhancements to the modem.

If, like me, you have been using the IOS5 Beta for development testing you may also want to be able to restore back to a previously jailbreakable version of IOS 4, most likely 4.3.3. If you try and do this with the 04.11.08 baseband on your phone you will be in for a world of pain, especially if you are also using the iTunes 10.5 beta as trying to downgrade straight to 4.3.3, even if you have saved SHSH Blobs, will result in a DFU loop. Even if you can fix this, residual problems remain including a loss of your APN settings which need to be restored manually. Very annoying

However, it is possible to downgrade the baseband to 04.10.01 by downgrading back to 4.3.5

IMPORTANT NOTE - This method will only work whilst Apple is still signing the 4.3.5 firmware and its associated 04.10.01 baseband. As soon as IOS5 goes gold and Apple close the 4.3.5 signing window, this method will cease to work.

UPDATE - 17/10 @ 20:55 - Unfortunately I have just tested the signing window with iSHSH1T, and it appears as though it has just been closed. I am being refused blobs for 4.3.5 from Apple. Looks like anyone who has not got this to work is now out of luck... Sorry.

2. Ensure your hosts file is pointing at Apple. You can do this easily with TinyUmbrella. Simply open it, switch to the Advanced tab, UNTICK the option "Set Hosts to Cydia on Exit", and then exit TU. DO NOT USE TU FOR ANY OTHER PART OF THE PROCESS!
Alternatively you can edit your hosts file manually if you are so inclined. Ensure you remove all lines which refer to gs.apple.com.

4. Open iTunes, which will recognise your iPhone in recovery mode, acknowledge the message about this, then press shift-restore (Windows) or option-restore (OSX), and select the 4.3.5 firmware you downloaded in step 1.

5. If you followed the instructions, the restore to 4.3.5 should now complete without any errors. When it is complete you will have a stock 4.3.5 iPhone4 again with a downgraded 04.10.01 baseband. Bonus!

Here are my before and after "About" screenshots showing that the baseband was downgraded (as well as the differences in About screens between the versions!).
Remember, the baseband cannot normally be downgraded, however because Apple are signing both the beta and current firmwares, and their associated basebands, it is possible, but only until the official release of IOS5.

Now you should be able to go on further (if required) and downgrade 4.3.5 to 4.3.3, IF you have saved SHSH Blobs for 4.3.3 available. Because your baseband has been downgraded to 04.10.01 you will not end up in a nasty recovery or DFU loop. Remember, there is no way to downgrade further unless you have saved SHSH Blobs. See our guide here for more details - http://www.iphoneforums.net/forum/i.../shsh-blobs-frequently-asked-questions-19986/

Hello people,
I am new to this forum as well as to the iphone I am currently using Gevey in order to use my phone with my current provider. I am worried about ios 5 coming out on the 12th and loosing my phone So my question is, can I stay on Ios 4.3.5 and not upgrade until Gevey addresses the new baseband, or do I HAVE TO upgrade to ios 5 and jailbreak? My baseband version is 04.10.01. Thanks a bunch.

Hello people,
I am new to this forum as well as to the iphone I am currently using Gevey in order to use my phone with my current provider. I am worried about ios 5 coming out on the 12th and loosing my phone So my question is, can I stay on Ios 4.3.5 and not upgrade until Gevey addresses the new baseband, or do I HAVE TO upgrade to ios 5 and jailbreak? My baseband version is 04.10.01. Thanks a bunch.

Click to expand...

No, you don't have to update. This is always optional when you plug into iTunes. In your case you must NOT update, otherwise the new baseband will block the Gevey.

PLEASE NOTE - IOS5 and the new baseband will be released in 2 days. This guide will only remain valid until such time as Apple stop signing 4.3.5 / 4.2.10, so you need to act now if you have been trying out IOS5 beta / GM and want to get back to 4.3.x and the associated baseband before IOS5 goes public!

Otherwise you will be stuck on the new baseband. That may or may not be a bad thing for you.

PLEASE NOTE - IOS5 and the new baseband will be released in 2 days. This guide will only remain valid until such time as Apple stop signing 4.3.5 / 4.2.10, so you need to act now if you have been trying out IOS5 beta / GM and want to get back to 4.3.x and the associated baseband before IOS5 goes public!

Otherwise you will be stuck on the new baseband. That may or may not be a bad thing for you.

You have been warned!

Click to expand...

Do you guys think that Gevey will eventuall address this new baseband or are we pretty much screwed?

Guys i have messed up and upgraded my phone to ios 5 without preserving the base band it was 04.10.01 and now its the latest one....!! any one with any help i will be greatfull....! thanks in adavnace.

Hey addy, I did the same thing and what worked for me, first download a 4.3.5 firmware off redsnow and put it in a folder on desktop. Then I had an older itunes installed on my wifes computer so i put my phone in dfu and plugged it in. It will tell you about dfu then hold shift down and hit restore and find your save firmware double click and walaa. Im back on 4.3.5 with 4.10.01 and using my gevey again hope this helps

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